>> there is definitely increasing worry in the united states administration about in whose hands these weapons are falling. >> these two stories on this special edition frontline. >> frontline is made possible by contributions to your pbs station from viewers like you. thank you. and by the corporation for public broadcasting. major funding is provided by the john d. and catherine t. macarthur foundation, committed to building a more just, verdant and peaceful world. and by reva and david logan, committed to investigative journalism as the guardian of the public interest. additional funding is provided by the park foundation, dedicated to heightening public awareness of critical issues. and by tfrontline journalism fund, supporting investigative reporting and enterprise journalism. >> narrator: guardian reporter ghaith abdul-ahad's journey into syria began five weeks ago on a supply route the rebels use to bring weapons from neighboring turkey. >> this is all liberated territory at the moment. >> narrator: the rebels are fighting to overthrow president bashar al-assad. every night the